Boring-bar



JACOB VAN DER VORN.

BORING BAR. APPLICATION FILED JULY 3.1919.

1,400,642, Patented Dec. 20, 1921,

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Applciation filed July 3, 1919.

To all whom it may concern:

Be it known that I, decor: VAN DER VonN, s citizen of the United States,and a. resident of Chicago, in the county of Cook and State of Illinois.have invented certain new and useful improvements in Boring-Bars. ofwhich the following is e frll, clear, and exact specification.

My invention relates to improvements in boring-bars for metal working,and more particularly to boring-bars oi the expansion type whereindiametrically arranged cutters or nujustsble to and from the axis of thebar for varying the diameter of the bore.

The prime object or the invention is to provide :1 boring-bur, havingdiametrically opposed cutters with. removable threaded nieins ndspted tobe inserted in the cutters for coiig ieret on with on adjusting screwhaving rcve l7 disposed tl" ;ids, whereby removal of .ither the cuttersor threaded I of wear or breakage. is rendered much more economical thanif these parts were integrally formed. Moreover. in such a constructiointhe proper variation in quality and hardness of steel for tho cuttersand threads which perform different functions more readily attained.

further object to provide a gradueted disl so arranged relative to anadjust ing screw for varying the positions of cutters in a boring-burthat the operator may determine at n .ing made by turning said screw.

And. it further object is to provide it locking-key for cutters or suchform and dimensions as to prevent distortion of the cooperating ports inthe boringdisr when subjected to heavy pressure. Other objects willappear hereinafter.

With these objects in view my invention finds embodiment in certainfeatures of construction, of novelty in the construction. combinationand srmn ement or" parts, by which said objects and certain otherobjects are attained, all as hereinafter described with reference to theaccompanying drswings and more particularly pointed out in the appendedclaims.

In said drawings:

Figure 1 is a side elevation of aboringbar constructed in accordancewith the present invention.

Fig. 2 is a. partial side elevation of the bar taken right angles tothat of Fig. 1.

Specification of Letters Patent.

hes the exact variation be.

Patented Dec. 2'0), 1921..

Serial No. 308,551.

Fig. 3 is a central vertical section taken on line 33 of i.

Fig. 4c is a section similar to Fig. 8 taken on line 4--& of Fig. 2.

Fig. 5 is an enlarged fragmentary section taken on the SELIDG plane asrind Fig. 6 is a detail perspective view showing a removable threadediloclr employed in the boring-bar.

The preferred form of construction as shown in the drawings comprises acylindrical body formed integrally with. a tepered shank One end of body1 is provided with a transverse slot 23 for the reccption ofdiametrically opposed a table cutters 4i and 5, which project an erpizildistsnce from opposite sides of said body, as shown in Fig. 2.

Cutters 4 and 5 are provided with reces es in one edge thereof intowhich rectsng ir threaded blocks 6 and 61 are pressed respectively, thefit of said blocks in their respective recesses being such as to holdthem cnrely, but not too tight to prevent eir ready removal in case itis des red to renew either the cutters or blocks.

The edges 7 off cutters +5; and 5 into which blocks 6 and 61 areinserted, are concuved in such a manner as to be in slineinent n th thebottom of threads 8 in said blocks, as shown in Figs. 1 and 5, saidthreads 8 cooperating with an adjusting screw 9 mounted in s boreprovided at the lower end of slot 3 in body 1. The threads 8 of blocks 6are right and left hand to lit correspond"1, threads 11 and 12 on screw9. From this construction it will be seen that the con.- caved surface*2 will contact with threads 11 and 12 to a certain. extent and thusrelieve blocks 6 and 61 of a part of the pressure when cutters e and 5are clamped in position.

The adjusting screw 9 is provided with s. medial reduced portion 13which. is sni rounded by an annular space into which a radial pin 14.-proj ects for maintaining said screw in proper position while beingturned for adjusting cutters l and 5, said pin being securely pressedinto body 1, as shown in Fig. 4. A square recess 15 is formed in one endof the adjusting screw 9 for the reception of a. T-wrench (not shownemployed for turning the same.

One end of the adjusting screw 9 is provided with e cliemetric line ands zero mark 5 the diametric line and zero mark 16 serv- 7 ing as dialpointer.

A. clamping pad 19 of rectangular form projects slightly beyond thelateral surfaces of body 1 and is provided with a central recess 20 forthe reception of a radial pin 21,,

whereby the pad is held in place during adjustment of the cutters. Pin21 1s retained by means of a short screw 22, as shown 1n Figs. 2 and 4.

An eccentric locking-key 23 arranged to cooperate with clamping pad 19for holding the cutters is somewhat shorter than the di ameter of body 1and is provided with reduced ends 2 1, whereby the length of contact onclamping pad 19 is shortened to such an Xtent as to preclude thepossibility of exerting any unresisted pressure on the cutter 4; and 5,which might result in distortion thereof. 11 circumferential groove 25is pro vided at the center of lockinghey 23, and a squared recess 26 atone end thereof, where by said locking-key may be readily turned forbringing the eccentric surfaces 27 thereof'into contact with clampingpad 19, as shown in Fig. 4. A pin 28 projects into groove 25 in such amanner as to permit the locking-key to turn freely and to preventendwise movement thereof, there being a pin retaining screw 29, similarto screw 22, screwed into body 1.

It will be noted that a transverse cylindrical bore 30 is provided forlocking-key 23, and that one side of this bore communicates with slot asshown in Figs. 1 and 1.

l rom the foregoing description it will be seen that a substantialboring-bar is constructed without employing threads on the cutters,inserted threaded blocks being employed instead. This feature isadvantageous for the reason that a threaded block can be removed from anold or worn out cutter and reinserted in a new cutter, thus saving thecost of furnishing new threads when only a new cutter is required.

While I have shown and described the pre- 'ferred construction forcarrying my invention into effect, there might be variations andmodifications without departing from the spirit of the invention. I,therefore, do notv wish to be limited to the precise details ofconstruction set forth, but desire to avail myself of such variationsand modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure byLettersPatent is:

1. A boring-bar, comprising a substantially cylindrical body having atransverse slot therein, a pair of diametrically opposed cutters mountedin said slot, an adjusting screw having reversely disposed threadsarranged contiguous to said cutters, and threaded blocks removablyinserted in said cutters with only their surface adjacent the screwprotruding, and said surfaces being threaded to cooperate with thescrew.

2. In a boring-bar, the combination of a cylindrical body and a shankformed integrally therewith, of a pair of radially projecting cuttersmounted in said body, and means for adial adjustment of said cutterscomprising a right and left-hand screw mounted adjacent thereto, andremovable solid screwthreaded blocks inserted in said cutters with onlythe surface adjacent the crew protruding, said surfaces beingscrewthreaded and cooperating with said screw.

3. In a boring-bar, the combination of a cylindrical body having acentral longitudinally extending slot therein, of a pair of radiallyextending cutters mounted in said slot so that the inner ends thereofare adaptd to meet on a line coincident with the axis of said body, arevolving screw arranged parallel to said cutters and disposed adjacentone edge thereof, means for preventing endwise movement of said screw,the latter hav ing riohthand threads on one end and lefthand threads onthe other, a removable solid block inserted in one cutter havingexternal righthand threads for cooperation with one end of said screw,and a removable solid block inserted in the other cutter having externallefthand threads for cooperation with the other end of said screw, withonly the surfaces of said blocks adjacent the screw protruding.

In witness whereof, I have hereunto set my hand and aliixed my seal,this 30th day of June, A. D. 1919.

JACOB VAN DER VORN.

